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Hi, How do i generate a delay of 50nS using C.is there any NOP instruction in ARM7.i dont want to use timer or interrupt.please help
Regards, Divya
See: www.8052.com/.../read.phtml
Includes links to the UK National Physical Laboratory, and the US National Institute of Standards and Technology - in case you doubt the credentials of posters here...
Hi, Thank you for letting me know the SI systems,everybody here is trying to be smart explaining me the units, no one pointing to the problem i am facing. LPC2129 will be generating only one task,that is of 10MHz frequency generation.
Datasheets of LPC2129 says the slew rate of I/O pin is 10ns, and with 60 Mhz osc frequency the 1 machine cycle comes out to be 16.666ns.So 3 cycles are well enough to generate 50ns.Please tell me where can i find the machine cycles details of ARM7 instructions.
No hard feelings friends,i said what is truth.
"Please tell me where can i find the machine cycles details of ARM7 instructions."
No hard feelings, but if you are so clever, you should be able to find them yourself.
i said you answer before!
use your internet and seearccch!!!
i found more 1000000 matches for dociment
try www.simplemachines.it/.../arm_inst.pdf
I have the instruction set with me,however i dont find the machine cycles required for each instruction.
We are not here for a debate,I think people are here to help each other and not to find who is clever and who isnt.
For details of the ARM architecture itself, go to http://www.arm.com
"LPC2129 will be generating only one task, that is of 10MHz frequency generation."
If that's really the one and only thing its doing, why do you need an ARM? In fact, why do you need any processor at all?!
Surely, this is just a simple oscillator or frequency divider?!
"So 3 cycles are well enough to generate 50ns."
and the processor will have absolutely no time left whatsoever to do anything else at all - so it really is just being a glorified oscillator or frequency divider! What a waste of an advanced 32-bit processor!
Running the chip at 60MHz just to get 10MHz, would probably be a contender for the worlds most power-inefficient 10MHz generator... If complemented with interrupts for other functions, it would also be the worlds most unstable frequency generator.
1) You wouldn't have got a long discussion about SI units, unless your answer to my footnote was that nS really did mean nanoseconds. That was a schoolbook example of how to start a debate.
2) You have never told us how much jitter and frequency error you can accept.
3) You have never told us why you do not want to look at the timers. Just "wanting to" is not a reason.
4) Your original post talked about a 50ns delay, instead of a 10MHz frequency. Only in a theoretical world are the two concepts interchangeable.
5) You have not told us if you need just a short burst, or if you need a continuous signal. A continuous signal needs time for a jump instruction too, since you can't have an infinitely unrolled loop. And a way to end the loop - unless the chip should generate 10MHz until power is removed... If you don't like timers/interrupts for the signal generation, then our assumption must be that you don't like interrupts for ending the generation either! Hence, an if statement and a loop counter is required.
6) I - and most other people on this forum - don't need 10MHz output from the chip. However, the timers are in a class of their own when it comes to generation of square-wave output with low jitter and constant frequency with a minimum of power consumption and processor load. Since you - and not I - need 10MHz, my recommendation was for you to look in the data sheet for support for 10MHz using the timers.
Somehow, I get the feeling that if we don't post finished code for a 10MHz generator, you are not satisfied with our answers. Why do you expect that? And why no feedback why you only accept a sw solution, even if the chip has to more or less break it's back to manage it?
no one pointing to the problem i am facing
Oh, you did get quite a lot of answers pointing to the problem. You prefer to insist on every single one of your mistakes rather than listen to any of the advice you got, though.
And just in case you're suddenly prepared to actually listen, this:
only one task,that is of 10MHz frequency generation.
is totally the wrong problem to be solved the way you insist on. That task a) should never be done by a processor in the first place, and b) even if it really has to be done with a processor, should be done by its output-compare timer functions. What you've decided to do is equivalent to driving nails into hardwood using a cucumber, while you have both a perfectly workable hammer and a fully loaded nail-gun at hand.